Cutting mechanism for use in an electronic yarn cleaner



y 12, 1954 H. GLASTRA 3,132,407 CUTTING MECHANISM FOR USE IN AN ELECTRONIC YARN CLEANER Filed Oct. 11, 1961 CONTROL 0 To CIRCUIT WINDING 4- k\ l l \1-[- & y

--6 -2 N I I I INVENTOR HENDRIK GLASTRA AGEN United States Patent Ofiice Patented May 12, 1964 3,132,407 CUTTING MECHANISM FQR USE IN AN ELECTRGNIC YARN CLEANER Hendrik Glastra, Enschede, Netherlands, assignor to North American Philips Company, Inc, New York, N.Y., a corporation of Delaware Filed Get. 11, 196i, Ser. No. 144,383 9 (Ilaims. ((ll. 28-,-64)

The invention relates to a cutting mechanism for use in an electronic yarn cleaner, comprising an electro-magnet circuitand a cutter to be actuated thereby.

Electronic yarn cleaners are used in textile technique for removing thicker parts (slubs) and other irregularities from yarns. In a known yarn cleaner the yarn travels between the plates of a measuring capacitor and the cutter is actuated when an irregularity passes by. This cutting mechanism may be constructed in different Ways, but all known embodiments comprise a magnetic coil which directly attracts either the knife or an intermediate member coupled therewith.

It is desirable for such a cutting mechanism to operate quickly, i.e. to become operative within the shortest possibie time after the passage of a slub otherwise the yarn will be wound too far and the yarn then must be rewound to find the slub. With the known cutting mechanisms the air gap in the magnetic circuit is at a maximum in the rest position. The force exerted on the knife is therefore at a minimum, whereas it should be at a maximum at the instant concerned. It is obvious that this is not conducive to a quick operation of the mechanism.

A further disadvantage is the comparatively large size of the magnetic circuit required for obtaining adequate attractive forces. It is for this reason difficult to minimize the dimensions of yarn cleaners. i

The invention has for its object to obviate these disadvantages and in accordance with the invention the cutting member is coupled with a permanent magnet arranged movably in the magnetic circuit. 1 I i The cutting member preferably comprises a knife supporting the permanent magnet, this combination being movably arranged in an air gap of the electromagnetic circuit. It is advantageous in this case to have the permanent magnet bear on one of the poles of the magnetic circuit in the rest position and to have the polarization direction of this circuit so that, when the circuit is energized, the magnet is repelled from this pole.

In a preferred embodiment the neutral zone of the magnet is approximately perpendicular to its side engaging the pole.

The advantage of the cutting mechanism according to the invention consists in that in order to obtain a reliable energization the magnetic circuit requires a considerably smaller amount of energy than in the case with the known cutting mechanisms. The dimensions may therefore be 1 smaller and owing to the reduction of the number of movable parts the construction is simpler and cheaper. Even a return spring is no longer required, consequently, the risk of disturbances is reduced. 7

In order that the invention may be clearly understood and readily carried into effect, it will now be described more fully with reference to the accompanying drawing, in which FIG. 1 is a plan view of an example of the cutting mechanism according to the invention, combined with a measuring capacitor, and FIG. 2 is a perspective View of this embodiment.

The cutting mechanism comprises a magnetic circuit having two soft iron poleshoes 1 and 2, which are connected with each other by a soft iron connecting piece 3, supporting the magnet winding 4 '(FIG. 2). gap of this magnetic circuit provision is made of a steel In the air knife 5, of which one edge is accommodated in a recess 6 in the pole shoe 2. The flat knife 5 supports a small magnet 7, which remains urged against the pole shoe 2 in the rest position. The neutral zone of the small magnet extends approximately at right angles to'the knife.

A measuring capacitor is formed by a pair of spaced conductive plates 10 embedded in an insulating block 9. The yarn 8 is arranged to pass between these plates so as to vary the capacitance thereof proportional to variations in the diameter of the yarn. A control circuit 12 senses the variations in capacitance and provides a control signal at its output terminals proportional thereto. Circuits for detecting variations in the thickness of a material passing between the plates of a capacitor and producing a control signal responsive thereto are well known in the art. The specific form which the detection circuits may take do not form a part of this invention. One convenient form of circuit of the type referred to which is adaptable for use in the invention is shown in FIG. 2 in US. Patent 2,565,- 500' issued to Robert M. Ingham, In, on August 28, 1951; The output signal so produced is applied to energize the magnet winding 4 of the device of the present invention.

When the magnetic circuit is energized by a current passing through the coil 4 so that a south pole is produced at the pole shoe 2 and a north pole at the pole shoe 1, the south pole of magnet 7 is repelled from the pole shoe 2 of the electromagnet and the north pole is attracted to pole shoe 2 so that the cutting end tilts over towards the pole shoe 1, whereas the opposite edge remains in the recess 6. The cutting edge then cuts the yarn 8.

From the figure it appears that by the combination with the measuring capacitor 10, embedded in insulating material 9, a very compact unit can be obtained. The dimensions of a practical embodiment are, for example, 25 x 18 x 18mrns. and the volume is 8.5 cm. whereas a cutting mechanism of the conventional kind having its dimensions minimized as much as possible has a volume of 23 cm.

In the embodiment shown in the figures, the knife also supports a soft iron plate 11, which reduces the air gap in I the magnetic circuit, While with a given current a greater flux is produced.

What is claimed is:

1. Cutting apparatus comprising electro-magnet circuit means having a pair of pole pieces defining an air gap, a cutting member arranged in the proximity of the material to be cut, and a permanent magnet arranged for movement within said air gap upon energization of said electromagnet and operatively coupled to said cutting member, said permanent magnet having a rest position i in which the spacing between said magnet and one of said pole pieces is a minimum. 7 v

2. Cutting apparatus comprising electromagnet circuit means having a pair of pole pieces defining an air gap, a

cutting member and a permanent magnet secured together and rotatably' mounted within said air gap for movement upon energization of said electromagnet circuit means, said permanent magnet having a predetermined rangeof travel and a rest position defining one end of said range in which the spacing betweensaid magnet and one of said pole pieces is a minimum. I

3. Apparatus as defined in claim 2 wherein said cutting member comprises a fiat cutting blade on one side of which said permanent magnet is secured and on the other side of which is secured a plate of magnetic material.

4. Cutting apparatus for use in a device for cleaning I filamentary materials, which device includes means for cuit means responsive to said control signal and having a pair of confronting pole pieces defining an air gap, a cutting member to be actuated by said electromagnet circuit means arranged in the proximity of said material, and a permanent magnet rotatably mounted within said air gap and operatively coupled to said cutting member, said permanent magnet having a north and a south pole and a rest position in which said north and south poles both contact the same pole piece of said electromagnet circuit means.

5. Cutting apparatus comprising electromagnet circuit means having a pair of pole pieces defining an air gap, a cutting member arranged in the proximity of the material to be cut, a permanent magnet rotatably mounted within said air gap for movement upon energization of said electromagnet circuit means and having a pair of poles, said magnet being coupled to said cutting member and having a rest position in which said magnet contacts one of said pole pieces and wherein the magnetic neutral zone of said magnet is approximately perpendicular to the side of said magnet contacting said pole piece.

6. Apparatus as defined in claim 5 wherein upon energization of said electromagnet circuit means a magnetic field is produced having a direction such that one pole of said permanent magnet is repelled and the other pole of said permanent magnet is attracted to the rest position pole piece of said electromagnet circuit means.

7. Cutting apparatus for use in a device for cleaning filamentary materials, which device includes means for sensing a variation in one of the dimensions of the filamentary material beyond a predetermined value and means for producing a control signal in response to said variation, said apparatus comprising electromagnet circuit means responsive to said control signal and having a pair of pole pieces defining an air gap, a cutting member and a permanent magnet secured together and pivotally mounted within said air gap about a point on the face of one of said pole pieces, said permanent magnet having a rest position in which said magnet contacts one of said pole pieces and wherein said magnet is repelled from said pole piece upon energization of said electromagnet circuit means.

8. Cutting apparatus for use in a yarn cleaner device having means for sensing irregularities in the yarn and means for producing a control signal in response to said irregularities, said apparatus comprising electromagnetic circuit means responsive to said control signal and having a pair of pole pieces defining an air gap through which the yarn is arranged to pass, a knife and permanent magnet secured together and rotatably mounted within said air gap about a point on the face of one of said pole pieces, said permanent magnet having a rest position in which said magnet contacts one of said pole pieces, the energization of said electromagnet circuit means in response to said control signal producing a magnetic field to repel at least a portion of said magnet from the contacted pole piece in said rest position whereby said knife is moved into cutting relationship with said yarn, said permanent magnet producing a magnetic restoring torque to return said permanent magnet to said rest position upon deenergization of said electromagnetic circuit means.

9. Cutting apparatus for use in a yarn cleaner device having means for producing a control signal in response to irregularities in the yarn, said apparatus comprising means for sensing irregularities in the yarn comprising a pair of spaced apart electrically conductive plates through which said yarn is arranged to pass, said plates being disposed in a block of insulating material in the path of said yarn, electromagnetic circuit means responsive to said control signal comprising a core of magnetic material providing a substantially closed magnetic circuit having two confronting poles spaced apart to form an air gap and an energizing winding on said core, a cutting member and permanent magnet secured together and pivotally mounted within said air gap about a point on the face of one of said pole pieces, said permanent magnet having a rest position in which said magnet contacts said one of said pole pieces, the energization of said electromagnetic circuit means in response to said control signal repelling said permanent magnet to cause said cutting means to contact the yarn, said permanent magnet producing a magnetic restoring torque to return said permanent magnet to said rest position upon de-energization of said electromagnetic circuit means.

References Cited in the file of this patent UNITED STATES PATENTS 2,936,511 Wilson May 17, 1960 

1. CUTTING APPARATUS COMPRISING ELECTRO-MAGNET CIRCUIT MEANS HAVING A PAIR OF POLE PIECES DEFINING AN AIR GAP, A CUTTING MEMBER ARRANGED IN THE PROXIMITY OF THE MATERIAL TO BE CUT, AND A PERMANENT MAGNET ARRANGED FOR MOVEMENT WITHIN SAID AIR GAP UPON ENERGIZATION OF SAID ELECTROMAGNET AND OPERATIVELY COUPLED TO SAID CUTTING MEMBER, SAID PERMANENT MAGNET HAVING A REST POSITION IN WHICH THE SPACING BETWEEN SAID MAGNET AND ONE OF SAID POLE PIECES IS A MINIMUM. 